I am thinking your TPS is hanging up. Every once in a while, intermittantly, my bike was stalling on me, usually in city traffic, when I allowed the throttle to close. This wasn't something the bike ever did, so I knew something was wrong.
An easy way to check is to hook it up to TuneEcu, put it on the diagnostic screen, watch the TPS readout when you open the throttle, and let it snap closed. If it's hanging up, you will see it on the readout. It will be slow to return to 0.
Mine was hanging up, and I removed the o-ring which I felt wasn't needed, and then it worked fine. Oddly enough, about a year later, my TPS went dodgey, and I had to replace it altogether.
2002 Sprint St, RaceTech Springs and GVE, Reworked Shock, Raised Rearsets!
Zero Gravity DB Windscreen, CF Tankpad, 18T Front Sprocket, Fuel Pressure Regulator Mod
Quick Turn Throttle Mod, Michelin PR3, CF TOR, Corbin Seat, Luggage Rack